Related Experiment Videos
Effect of optical defocus on multifocal ERG responses.
1Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
Clinical & Experimental Optometry
|October 16, 2003
Summary
Optical defocus slightly reduces multifocal electroretinography (mfERG) macular responses. Full optical correction is recommended for accurate mfERG measurements to avoid diminished macular function detection.
Area of Science:
- Ophthalmology
- Retinal Physiology
- Visual Electrophysiology
Background:
- Multifocal electroretinography (mfERG) assesses topographical retinal function.
- Macular degeneration and other conditions can reduce mfERG K1 response magnitude.
- Previous studies on optical defocus effects on mfERG yielded inconsistent results due to poor controls.
Purpose of the Study:
- To investigate the impact of optical defocus on the first-order kernel (K1) response of the central retina.
- To utilize a well-controlled methodology to assess mfERG changes under defocus conditions.
Main Methods:
- mfERG was performed on 20 subjects using the VERIS 4.0 system.
- Optical defocus conditions included zero, +1.00 D, and +3.00 D.
- Implicit times and response amplitudes of n1 and p1 were measured in the central macula and paramacular regions.
Main Results:
- Implicit times of n1 and p1 showed no significant variation across defocus conditions or retinal regions.
- The response amplitude of n1 remained unchanged.
- A significant 12% reduction in the central macular p1 response amplitude was observed under +1.00 D and +3.00 D defocus.
Conclusions:
- Optical defocus induces a mild reduction in mfERG responses specifically at the central macula.
- Retinal periphery responses were not significantly affected by optical defocus.
- Full optical correction during mfERG testing is advised to prevent underestimation of macular function.